The Role of Noise in Systems with Two Symmetric Absorbing States
- Event time: 11:30am
- Event date: 20th October 2010
- Speaker: Dominic Russell (Formerly School of Physics & Astronomy, University of Edinburgh)
- Location: Room 2511, James Clerk Maxwell Building (JCMB) James Clerk Maxwell Building Peter Guthrie Tait Road Edinburgh EH9 3FD GB
For such systems a phenomenological Langevin equation has been proposed which has been shown to encompass all the observed critical behaviour. In essence this is achieved by varying the shape of the potential from which the drift term is derived in the Langevin equation. In this talk I will outline a microscopic model which explicitly allows us to vary the noise strength without altering the shape of the potential. By transformation of the spatially discrete Langevin equation obtained for this model from one with multiplicative noise to one with additive noise, a simpler diffusive potential picture is obtained. From this we observe the possibility of different ordering behaviour of the system according to the value of h which sets the strength of the noise in our model, and make lower bound predictions for h*, the transition point between the two ordering regimes. Finally, time permitting, I will derive the Allen-Cahn equation for curvature-driven coarsening which has formed the basis of our simulations.
This is a roughly weekly series of didactical blackboard talks focussing on some theoretical aspect of Condensed Matter, Biological, and Statistical Physics..